Spinning of artificial filaments and the like



March 6, 1934. w. I. TAYLOR 1,949,983

SPINNING OF ARTIFICIAL FILAMENTS AND THE LIKE Filed Sept. 27, 1930ooooboo\ooooo WJLUAM I. TAYLOR WVE'NTUR ATTUHNEYS Patented liter. 19334UN' i-i PATENT OFFICE SPINNING OF ARTIFICIAL FILAMENTS AND THE LIKEApplication September 27, 1930, Serial No. 484,788 In Great BritainNovember 25, 1929 11 Claims.

This invention relates to the production of filaments, ribbons, straws,and the like from solutions of cellulose derivatives, for example,cellulose acetate, and is an improvement in or modification of theinvention described in U. S. application S. No. 375150 filed 1st July,1929.

According to the above specification, the setting or solidification ofthe filaments, threads, or the like (hereafter referred to as threads)is eijiented by evaporating the solvent liquid from the extruded threadsby means of a vacuum, or reduced or sub-atmospheric pressure. Theevaporation may be accelerated by heat, or by the use of a current or"air, or other evaporative me- Hi dium, or by using both these agenciesin conjunction with the application of a vacuum or reduced pressure. Incarrying out such process a solution or" the cellulose acetate or othercellulose derivative in a volatile solvent mixture is exf truded throughjets or spinnerets into a closed chamber or cell which is evacuated bymeans of a rotary or reciprocating air pump, a jet pump,

or an ejector or other appropriate apparatus for producing a vacuum, orsub-atmospheric pressure.

The threads, after they are hardened by evaporation, are led to awinding, or winding and twisting apparatus, outside the cell, being ledfrom the cell through an opening in the cell wall,

' which opening may comprise a pin-hole which is kept of smalldimensions to reduce to a minimum the amount of air entering the cellthrough the hole by reason of the degree or" vacuum existing Within thecell.

The present invention is concerned with methods of spinning under avacuum or reduced pressure employing the form of apparatus justmentioned, one object to provide means whereby the thread of filamentsmay be drawn from the spinning cell without allowing any appreciableinflux of atmospheric air, and especially moist air, into the cellthrough the opening by which the thread leaves the cell.

A dry spinning apparatus according to one feature of the inventioncomprises a spinning cell, a spinning jet in the cell, means forproducing a vacuum or a sub-atmospheric pressure in the cell, an openingfor withdrawing filaments from the cell and means by which the size ofthe opening may be adjusted to a small aperture whose size does notsubstantially exceed the cross-section of the thread. The opening in thespinning cell is of a size enabling the thread proceeding from the jetto be readily brought to the exterior of the cell for leading to acollecting device, and the size of the opening can then be reduced, e.g. by means of a sliding or pivoted plate, until there is justsufiicient space for the thread to pass without danger of the filamentsbeing rubbed or torn.

According to a further feature of the invention, means may be providedby which the region of the aperture through which the thread passes maybe supplied with dried air, so that moisturebearing atmospheric air isprevented from entering the cell through the aperture. This object maybe achieved by causing a jet or jets of dry air to impinge on the wallof the cell round the aperture, or by flooding the region of theaperture with dry air. For the purpose of keeping the dry air in theregion of the aperture and to reduce the amount of air to be supplied, ahood or cowl may be arranged round the aperture.

A form of apparatus according to the invention will now be described ingreater detail with reference to the accompanying drawing, but it is tobe understood that this description is given by Way of example only andis in no respect limitative.

Fig. 1 is a sectional side elevation of a vacuum spinning cell fittedwith the means according to the invention;

Figs. 2 and 3 are a front elevation and a plan, partly in section, ofthe thread removing means according to the invention, as applied to acylindrical spinning cell;

Figs. l, 5 and 6 show different forms of thread opening according to theinvention.

Referring to Fig. 1, the dry spinning apparatus shown therein comprisesa cell 11 fitted with a spinning solution supply pipe 12, a filter 13and a spinning jet 14, from which are extruded a number of filaments 15.A door 16 in the rear wall of the cell renders the jet is accessible. Avacuum is maintained in the cell, the solvent vapours and other gasesbeing carried oii by means of the pipe 1'? to a solvent recovery plantties, by the pipe 18. The vacuum is initially obtained by exhausting thecell through the pipe 19, and is maintained by suction through the pipe1'7, a vacuum gauge 20 being provided to indicate the degree of vacuumin the cell. Heating pipes 21 to maintain the required temperature inthe cell may also be provided.

The details of the opening by which the thread is removed are clearlyshown in Figs. 2 and 3 with reference to a cylindrical cell.

The front wall or" the cell is cut away to form a circular opening 22 ofsuificient size, say, of 2" diameter to allow the thread 15 extrudedfrom the jet 14 in the cell to be seized and drawn to the outside of thecell, and about an axis 23 at one side of the opening 22 is pivoted aplate 24 whose lower edge is shaped to form a notch 25 with a roundedapex, which, when the plate is in position, just clears the lower edgeof the opening 22 as shown in Fig. l. Alternatively, as shown in Fig. 5,the notch may be formed in the edge of the opening 22 and almost closedby the plate 24, or, and preferably, as shown in Fig. 6, both opening 22and plate 24 may be notched, so that the two notches form asubstantially circular opening when the plate is in position.

The aperture 26 which is left when the larger opening 22 is closed ispreferably about l/64= inch in width or diameter, so leaving only aslight clearance when the thread 15 is passing from the inside to theoutside of the cell 11. The edges of the aperture 26 should be smoothand rounded to avoid rubbing of the filaments. The filaments 15 are ledout of the cell by the aperture, round a feed roller 28 and on to thecap spinning device 29 by which they are collected as twisted thread.

A slot 30 on the side of the plate opposed to the pivot 23 engages astud 31 on the wall of the cell 11 when the plate 24 is closed, and thisstud and the pivoting stud of the plate are provided with wing nuts 32,by means of which the plate 24 is held in place while being readilyremovable. The plate is packed on its inner surface with rubber or othersuitable packing 33, and forms an airtight joint with the casing. Anabutment may if desired be provided to ensure that the plate alwaysassumes a definite position in which the small aperture has the correctdimensions and, if necessary, this abutment be adjustable, as by theprovision of a micrometer screw, to regulate the size of the opening andcompensate for any wear at the pivot of the plate.

Arranged around the opening in the cell wall is a metal hood 40, eitherof sufiicient size to allow the plate 24 to be opened inside it orprovided with a slot ll to enable the plate to be swung clear of theopening 22. A pipe or jet 42 attached to the hood by means of nuts 43connected by means of a pipe 44 to a suitable supply of dry air isarranged to -direct air to the inside of the hood 40, and preferablytowards or on to the small aperture 26 from which the thread 15 emerges.A valve is preferably arranged to cut ofi the supply of air while thethread is first being drawn through the aperture, but this valve is notshown in the drawing. When the plate is turned into position, so thatthe required sub-atmospheric pressure can be maintained in the cell, thevalve is opened and the ingress of moist air to the cell is effectivelyprevented by the jet of warm dry air with which the hood 40 is flooded.

What I claim and desire to secure by Letters Patent is:-

1. Process for the production of artificial silk or other filaments orthreads, or ribbons, tapes,

straws or the like by the evaporative method from solutions of cellulosederivatives comprising extruding a spinning solution into an evacuatedzone, leading the extruded product from said zone, and supplying dry airto the region of the point of emergence of said products from the zoneso as to prevent the ingress of moist air to said zone.

2. Process for the production of artificial silk or other filaments orthreads, or ribbons, tapes, straws or the like by the evaporative methodfrom solutions of cellulose derivatives comprising extruding a spinningsolution into an evacuated zone, leading the extruded product from saidzone, and supplying dry heated air to the region of the point ofemergence of said products from the zone so as to prevent the ingress ofmoist air to said zone.

3. Apparatus for spinning artificial silk, or other filaments, orthreads, or ribbons, tapes, straws, or the like from solutions ofcellulose derivatives comprising a spinning cell, a spinning jet in saidcell, means for producing a vacuum within the cell, an opening forwithdrawing the extruded products from the cell, means for reducing theopening to a small aperture whose size does not substantially exceed thecross-section of the filaments or the like, and means for supplying dryair to the region of said aperture outside the cell.

4. Apparatus according to claim 3, comprising a plate adapted partly tocover the opening whereby the edge of the plate and the edge of theopening form an aperture whose size is not substantially greater thanthe cross-section of the extruded products, and a hood or cowl adaptedto maintain the dry air in the region of the aperture, said hood or cowlbeing provided with a slot to allow the plate to be moved away from theopenmg.

5. Apparatus for spinning artificial silk or other filaments or threads,or ribbons, tapes, straws, or the like from solutions of cellulosederivatives, comprising a spinning cell or chamber, a spinning jet inthe said cell, means for producing a vacuum or sub-atmospheric pressurewithin the cell, an aperture for leading filaments or the like from thecell, and means for supplying dry air to the region of the said apertureto prevent moist air from entering the cell through the aperture.

6. Apparatus according to claim 5 comprising a nozzle adapted to directa jet of dry air towards the aperture.

7. Apparatus according to claim 5 comprising a cowl-like membersurrounding the orifice and adapted to maintain the dry air in theregion of the aperture.

8. Process for the production of artificial silk or other filaments orthreads, or ribbons, tapes, straws or the like from cellulose acetatecomprising extruding a spinning solution into an evacuated zone, leadingthe extruded product from said zone, and supplying dry air to the regionof the point of emergence of said products from the zone so as toprevent the ingress of moist air to said zone.

9. Process for the production of artificial silk or other filaments orthreads, or ribbons, tapes, straws or the like from solutions ofcellulose acetate comprising extruding a spinning solution into anevacuated zone, leading the extruded product from said zone, andsupplying dry heated air to the region of the point of emergence of saidproducts from the zone so as to prevent the ingress of moist air to saidzone.

10. Apparatus for spinning artificial silk or 150 form by the apices ofthe two notches an aperture whose size is not substantially greater thanthe cross section of the filaments or the like.

11. Apparatus according to claim 10 comprising means adapted to limitthe position of the plate, and to allow the size of the aperture to beadjusted.

WILLIAM IVAN TAYLOR.

